Update changelog for v0.16.0

[gha-automation-personal]

Changes

This PR prepares the changelog for release v0.16.0

🚀 New Features

• Upgrade to .NET 10 by @Copilot in Upgrade to .NET 10 #393
• Update to System.CommandLine 2.0.0 by @geofflamrock in Update to System.CommandLine 2.0.0 #394

Other changes

• Simplify loading and saving of stacks in handlers by @geofflamrock in Simplify loading and saving of stacks in handlers #386
• Reorganise stack persistence and model folder structure by @geofflamrock in Reorganise stack persistence and model folder structure #389
• Remove remote uri from core stack domain by @geofflamrock in Remove remote uri from core stack domain #390
• Fixes issue where changes to branches in stack would not be saved by @geofflamrock in Fixes issue where changes to branches in stack would not be saved #391
• Verify published binaries run before archiving in CI by @Copilot in Verify published binaries run before archiving in CI #398

Releasing the new version

When you are ready to release the new version, merge this PR, then create a release in the repository with the tag v0.16.0.